The training protocol was started at this time to evaluate the role of physical training in reversing or decreasing the harmful effects of the estrogen deficiency.

Exercise training was performed in a swimming pool (180 cm × 70 cm × 60 cm) filled with tap water warmed to approximately 30–32 °C at the same time of day (14:00–16:00 pm) in all training sessions during 8 weeks. The exercise intensity was progressively increased over the first two weeks. learn more In the first day, the rats swam for 10 min, and swim time was increased until the rats were swimming for thirty minutes on the fifth day. In the second week, the swim time was increased each day until the animals could swim for 60 min while wearing a caudal dumbbell, weighing 5% of their body weight (overload) [43]. This protocol has previously been characterized as low to moderate intensity (with a long duration) based on improvements in muscle oxidative capacity [33]. The coronary function of rats was evaluated using the Langendorff preparation (Hugo Sachs Electronics™, March-Hugstetten, Germany). Forty-eight hours after the last exercise session, the animals were killed

by decapitation. After decapitation, their thorax was opened and the hearts were rapidly excised and placed in ice-cold modified Krebs buffer. The aorta was immediately cannulated with a 21 G needle and perfused with a modified Krebs buffer (composed of 120 mM NaCl, 1.26 mM CaCl2·2H2O, 5.4 mM KCl, 2.5 mM MgSO4·7H2O, 2 mM NaH2PO4·H2O, Avelestat (AZD9668) see more 27 mM NaHCO3, 1.2 mM Na2SO4, 0.03 mM EDTA, and 11 mM glucose). The Krebs buffer was equilibrated with a carbogen mixture (O2

95% + CO2 5%, White-Martins Ind., RJ, Brazil) at a constant pressure of 100 mmHg to give a pH of 7.4 and kept at 37 °C. The perfusion flow was maintained at a rate of 10 mL/min by a peristaltic pump (MS-Reglo 4-channel, Hugo Sachs Electronics™), according to the Langendorff methods [35] and [47]. After a small surgical incision in the left atrium, isovolumetric cardiac pressure was recorded with a water-filled latex balloon (Durex, London, UK) inserted into the left ventricle (LV) through a steel catheter connected to a transducer (TPS-2 Statham transducer – Incor, Sao Paulo, SP, Brazil). The LV end-diastolic pressure was set at 8–10 mmHg by adjusting the balloon volume through a spindle syringe. The coronary perfusion pressure (CPP) and intrinsic heart rate (IHR) were continuously recorded with a sidearm of the aortic cannula with a pressure transducer (P23Db Statham transducer – Incor, Sao Paulo, SP, Brazil) connected to data acquisition system (PowerLab™, ADI Instruments, Bela Vista, NSW, Australia). After a stabilization period of 40 min, baseline values of CPP and IHR were determined. Then, the responsiveness of the coronary vascular bed was evaluated. A bolus injection (100 μl) of modified Krebs’s buffer was applied to determine volume-injection-induced changes in CPP and IHR.